Potato starch copolymers as superabsorbents of methylene blue from aqueous solutions.

Superabsorbent materials based on potato starch (St) grafted polyacrylamide (PAM) were synthesized by radical polymerization with ammonium persulfate as initiator. The N,N'-methylenebisacrylamide (MBA) was a crosslinking agent. Starch grafted polyacrylamides (St-g-PAM) and their hydrolyzed analogues were specified by XRay Diffraction, Fourier transform infrared spectroscopy, differential scanning calorimetry and thermal analysis. The studies confirmed the grafting of PAM into the starch backbone and partial alkaline hydrolysis of PAM. The sorption of methylene blue (MB) from aqueous solutions was investigated depending on the initial concentration of the MB solution, the contact time, the amount of PAM grafted onto starch and the structure of the sorbent (hydrolyzed or non-hydrolyzed material). In the case of non-hydrolyzed material, satisfactory sorption results (adsorption efficiency - 42 mg MB/g of sorbent and swelling mass - 1600%) were obtained for St-g-PAM with 40 wt.% of PAM (St 40PAM). On the other hand, the best results were achieved for the hydrolyzed material (H St 40PAM): 88 mg MB/g of sorbent and 2100%, respectively. [ABSTRACT FROM AUTHOR]